Explosion-safe boat hull construction

ABSTRACT

A boat hull having compartments with inner explosion-resistant walls recessed within the hull for enclosing engines, fuel lines, fuel tanks and other gas tanks, said compartments venting and draining outwardly to the hull fairing surfaces and having outer fairing surfaces detachable outwardly in response to internal explosions within said compartments.

United States Patent 1 Morse [111 3,765,041 [451 Oct. 16, 1973EXPLOSION-SAFE BOAT HULL CONSTRUCTION 3,371,362 3/1968 Butler 115/17Primary ExaminerDuane A. Reger Assistant Examiner-Jesus D. SoteloAttorney-Hamilton, Renner & Kenner [5 7] ABSTRACT A boat hull havingcompartments with inner explosion-resistant walls recessed within thehull for enclosing engines, fuel lines, fuel tanks and other gas tanks,said compartments venting and draining outwardly to the hull fairingsurfaces and having outer fairing surfaces detachable outwardly inresponse to internal ex plosions within said compartments.

4 Claims, 7 Drawing Figures [52] US. Cl. 9/6, 114/116, 115/34 R [51]Int. Cl. B63b 3/00, B63b 3/56 [58] Field of Search 9/1 R, 6, 3, 4, 9;

[56] References Cited UNITED STATES PATENTS 2,623,721 12/1952 Harrington244/135 R Patented Oct. 16, 1973 3,765,041

5 Sheets-Sheet 1 N N INVENTOR. J HN F. MOR E BY W 9 W ATTORNEYS PatentedOct. 16, 1973 3,765,041

5 Sheets-Sheet 2 INVENTOR.

JOHN F. MORSE ATTORNEYS Patented Oct. 16, 1973 5 Sheets-Sheet 3INVENIOR.

OHN F. MORSE ATTORNEYS Patented Oct. 16,1973 3,765.04}

5 Sheets-Sheet 4 0. INVENTOR.

JOHN F. MORSE ATTORNEYS Patented Oct. 15, 1973 5 Shets-Sheet 5 INVENTOR.

JOHN F. Mwniw 7 tzn/m ATTORNEYS 1 EXPLOSION-SAFE BOAT HULL CONSTRUCTIONBACKGROUND OF THE INVENTION Fire and explosion are the most gravehazards in relatively small power boats, particularly those powered byinboard gasoline engines. Explosions can occur as a result of carelessfuel handling resulting in gasoline fumes or spilled raw gasoline whichcauses a concentration of explosive fumes at low points in the bilge orengine chamber. Additionally, gasoline from the carburetor is vaporizedby the heat of the engine after engine shutdown. Also, in case offailure of the fuel pump diaphragm, liquid gasoline may collect at lowpoints within the hull and be vaporized. Other causes of concentratingexplosive gasolinefumes include leaking fuel tanks, loose connections,broken lines, and the like.

' Sources of other explosive vapors aboard boats are leaks in the tanksor connecting lines to pressurized tanks of liquid petroleum gas used incooking and heating and sewage holding tanks which may generate methaneor other. explosive vapors.

Once a pocket of explosive vapors has collected within a boat hull, itcan be ignited by a spark from electric switches or motors, or flamesfrom pilot lights of stove or water heater, or from lighting cigarettes,and the result is an explosion which may destroy the boat and seriouslyinjure or kill the occupants.

In many cases, diesel engines are used in small craft in order to reducethe Fire and explosion hazard because of the less volatile diesel fuel,but diesel engines are more costly and much heavier than gasolineengines, resulting in a substantial increase in overall boat t n a eqree ll99?.1991595'33???P y in smaller boats of under 40 feet in length.

The early U.S. Pat. No. 741,512 disclosed a recognition of the danger ofusing explosive fuel in a boat and attempted to remedy the situation. byan elaborate arrangement including an exposed pipeline extending alongthe keel outside of the hull with standpipes open to the watersurrounding the vertical branch'pipes connected at the ends ofthepipeline to the fuel tank and the engine. U.S. Pat. No. 2,119,281disclosed a sealed compartment in a boat for storing an auxiliaryoutboard motor in an inoperative position so as to prevent the escape offumes and liquids from the stored auxiliarymotor unit into the boat. Tooperate the motor it is removed from the compartment and mounted outsideof the hull. U.S. Pat. Nos. 2,764,119 and 2,842,086 show separatecompartments attached to the stern of a boat forhousing outboard enginesand fuel supply. These patents represent the most pertinent prior artknown to applicant. s

SUMMARY OFYTI-IE INvENrioN v The primary object of the present inventionis to provide an improved hull structure for gasoline powered inboardboats which is adapted substantially to prevent fire and explosion bydissipating explosive liquids and vapors outwardly from areas where theyotherwise become concentrated, and to direct outwardly of the hull anyexplosive forces which may occur, thereby preventing damage to the innerhulland injury to its occupants. i

Another object of the present invention is to provide an improved boathull which will enclose all hazardous equipment within the outer fairingbut outboard of the basic hull structure and in a manner to protect thehull structure from fire and explosion.

A further object is to provide recesses within the hull contours havingsloping walls and surfaces providing overboard draingage therefrom andaiding in directing explosion forces outwardly of said recesses.

A still further object is to provide detachably mounted outer covers forsaid recesses which continue the outer faring surfaces of the hull whileproviding drainage and vent openings, and are adapted to releaseoutwardly in response to excessive internal pressure.

Still another object is to provide an improved hull having recesses forenclosing hazardous or bulky equipment in such manner that the equipmentmay be installed, removed or repaired without removing decks or damagingthe hull structure.

These and other objects are accomplished by the improvements comprisingthe present invention, preferred embodiments of which are shown in theaccompanying drawings and described in the following specification.Various modifications and changes in details of construction areintended to be within the scope of the appended claims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic partial elevationalview, partly broken away and in section, of a boat powered by inboardtwin gasoline engines.

FIG. 2 is a plan sectionalview on line 2--2-of FIG. 1. 1 FIG. 3 is acrosssection on line 3-3' of FIG. 2. FIG. 4'is a partial elevationalview, partly in section, of the stern area of a larger boat normallypowered with diesel engines and having a sewage holding tank.

FIG. 5 is a plan elevational view thereof, partly in section.

FIG. 6 is a partial plan sectional view of the stern area of a boatpowered by an inboard engine having an""outdrive type of propulsion. 1

FIG. 7 is a vertical sectional view on line 77 of FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS nected to the propeller 15 by aconventional inboard V drive arrangement comprising the-drive shaft 16connecting the engine transmission 17 to the fV drive gear box 18 fromwhich the propeller shaft 19 is driven.

The usual rudder 20 for steering is mounted in the hull behindthe'propeller l5.

As shown in FIGS. 1 and 2, the twin engines 13 are completely enclosedwithin a compartment 21 recessed inwardly and forwardly of the sternfairing wall or transom 22. Comparment 21 is trapezoidal in crosssection and has an upright forward wall 23 through which a water andvapor type seal 24 extends for the drive shaft 16, with outwardlyinclined top, bottom and side walls 25, 26 and 27, respectively,extending rearwardly from wall 23. The engine platform 14 is supportedon bottom wall 26. The compartment walls 23, 25, 26 and 27 are actuallywatertight continuations of thehull walls, and

are preferably of strong, rugged material such as molded fiberglas orwelded metal, which is resistant to fire and explosive pressures.

By sloping the top, bottom and side walls outwardly from the forwardwall 23 rearwardly, the force of any explosion occurring in thecompartment is directed rearwardly of the hull. Also, the sloping bottomwall 26 is ideally arranged to terminate at the transom at or near waterlevel when the boat is at rest. The water level at rest is indicated at28 in FIG. 1.

A lightweight fairing or cover plate 30 extends across the open rear endof the compartment 21 to substantially close the compartment. This coverplate may be of thin aluminum or fiberglas sheet, and is mounted foroutward detachment from the compartment by means of attaching screws 31securing the cover to upright bars 32 extending between top and bottomwalls and 26. In case of an explosion within the compartment 21, thecover is easily blown off to release the explosive pressure and preventconfining the explosion within the compartment. At the same time thecover 30 prevents excessive surging of sea water into the comparment andis braced against the inward pressure of the water by the support bars32.

An opening 34 along the bottom of cover plate 30 allows a restrictedamount of sea waterto flow in and out of the compartment 21 when theboat is at rest and allows water to drain from the compartment when theboat is under way. Also, the sloping bottom wall 26 drains any volatilefuel which has leaked or been spilled into the compartment to thetransom where it is carried away through the opening 34, thus greatlyreducing the tire and explosion hazard. Conventional air scoops 35located outboard of the cabin l1 allow air to flow through ducts 36 toventilate the compartment 21 and dissipate any fumes therein throughpreferably peripheral' vents 37 around the top and sides of cover plate30. Louvers 38 may also be provided in the cover plate 30, ifdesired. A

As shown in FIGS. 2 and 3, similar fire and explosion-' resistantcompartments 40, recessed within the outer fairing of the sides of thehull, may be provided for the fuel tanks 41. The compartments 40 haveinner upright walls 42, and. top, bottom and side walls 43, 44 and 45,respectively, extending outwardly therefrom to the outer fairings of thehull 10. Some or all of the top, bottom and side walls are inclinedlaterally outwardly, as shown, to direct explosive forces from withinoutwardly of the hull. Extension compartments 46 for the tank fillerpipes 47 are preferably provided above the compartments 40 and haveinner upright walls 48 outside of the cockpit area 49.

Lightweight cover plates 50 similar to covers 30 may be provided incontinuation of the outer fairing walls 51 of the sides of the hull forcovering and protecting the open sides of both compartments 40 and 46,the covers being mounted for outward detachment similarly to the covers30 on compartment 21-. Openings 52 are provided in said covers 50 foraccess to the filler pipes 47. In case of spillage within thecompartments the gasoline will drain out of the bottoms, and in case ofexplosion within said compartmnets the covers are easily blown off.Drain openings 53 are provided along the bottom edges of the coverplates 50, the openings being at the water level when the boat is atrest, and suitable vent openings may be provided along the side and topedges of the covers.

Ducts 55, carrying the fuel lines from fuel compartments 40 to enginecompartments 21, are made of the same tire and explosion-resistantmaterial as the hull compartment walls so as to isolate them fromcommunication with the interior of the hull, and may slope or drain toeither compartment. They are preferably arranged to induce air flow fromthe compartments 50 to the compartments 21 to assist in removing anyaccumulation of liquids or vapors.

The embodiment of FIGS. 4 and 5 shows an arrangement of a recessedcompartment in the stern area of a larger boat 10' which might normallybe equipped with diesel propulsion comprising diesel engines 56 drivingpropellers 57. In boats of this size, the usual relatively large sewageholding tank located within the hull structure presents a hazardouscondition because of possible explosion within the tank of methane gasand other explosive vapors inherently developed within such a tank. Inthis case, the recessed compartment 58 is formed inwardly and forwardlyfrom the transom area and has walls similar to those formingcompartments 21 and 40, and the compartment may be covered by fairingcover 59 attached to supporting bars 59' and having drain openings alongits bottom edge and vents at its top and side edges. Sewage holding tank60 may be constructed of lightweight metal, molded fiberglas or plasticmaterial and is retained within the compartment by tie-down straps 61,with the tank resting on supporting rails 62. Sewage lines 63 arebrought through the inner wall 64 of recessed compartment 58 by means ofvapor and watertight connections 65 and into the top of tank 60 at 66. Apump-out connection 67 may extend through the fairing cover 59 and havea suction pipe 68 extending to the lowest point of tank 60. Suitableconventional vent connections at 69 are provided to ventilate the tank.

Construction of the sewage holding tank is such as to allow sufficientstrength to support the contained liquids but to allow rupture along theback wall in case of an internal explosion, in which case the forceofsuch explosion would be directed outwardly and in this case to the rearand blow off fairing cover 59.

In the embodiment of FIGS. 6 and 7, the boat 10" is provided withso-called out-drive propulsion having an inboard gasoline engine'70,heavier than the conventional outboard, driving the propeller 71 bymeans of an outboard drive assembly indicated-generally at 72, which isused for steering when in operation and arrangedto swing upwardly whennot in operation.

This type of drive is frequently used'in a large number of smallpleasure boats by inexperienced persons who tend to be careless withregard to gasoline spillage and leakage, especially because they assumethat this type of propulsion is comparable in safetyto the conventionaloutboard engine which is wholly outside of the hull. As a result, adisproportionately large number of fire and explosion accidents haveoccurred with boats having out-drive propulsion.

The engine is mounted in the recessed compartment 73 on a suitablesupport platform 74 which is carried on bottom wall 75 slopingrearwardly outwardly from the forward inner upright wall 76 of thecompartment. Preferably, the side walls 77 of the compartment also sloperearwardly outwardly to direct explosive forces to the rear, and alightweight fairing cover 78 normally closes the rear open end of thecompartment, being mounted for outward detachment in case of explosion.Vent and drain openings are provided around the cover 78.

If desired, a service hatch 80 of molded fiberglas or the like may behinged at 81 to the top of the compartment with some slight sacrifice tothe complete protection when the engine is completely enclosed by fireand explosion-resistant walls. Obviously, the fuel tank and any sewagetank for this embodiment may be enclosed within separate compartmentsrecessed within the hull, similarly to those disclosed in FIGS. 1 5.

The improved boat hull construction provides for containing all thehazardous equipment within separate fire and explosion-resistantcompartments recessed within the hull so as to protect the hullstructure. The bottom walls of the compartments drain outwardly toremove any accumulation of explosion-causing liquids. The walls of thecompartments contain fire and direct explosion pressures outwardly, andfairing covers mounted for outward detachment enclose the compartmentsin continuation of the hull surfaces. The compartments facilitateinstallation, repair and removal of large or hazardous equipment withoutremoving or damaging decks and inner hull structure.

What is claimed is:

1. Boat hull construction comprising walls forming sideand transomfairing surfaces determining the outer contour of said walls, said wallsrecessed inwardly from at least one of said fairing surfaces to formseparate compartments for a fuel tank and an engine and adapted toresist explosive pressures within said compartments, at least one of thewalls of each compartment being sloped toward said fairing surface todrain liquids and direct explosive forces outwardly from saidcompartment, and explosion-resistant ducts connecting said compartments.

2. Boat hull construction as in claim 1 in which the compartment for theengine is recessed inwardly from the transom and the compartment for thefuel tank is recessed inwardly from one side of the wall.

3. Boat hull construction as in claim 2 in which covers in continuationof said outer wall fairing surfaces are outwardly detachably mounted onsaid compartments.

4. Boat hull construction comprising walls forming side and transomfairing surfaces determining the outer contour of said wall, said wallsrecessed inwardly from said transom fairing surface to form an enginecompartment adapted to resist explosive pressures within saidcompartment, at least one of said compartment walls being slopedoutwardly toward said fairing surface to drain liquids and directexplosive forces outwardly from said compartment, said compartmenthaving an upright forward wall, an engine mounted in said compartmentfor propelling the boat through a forward gear box, and a drive shaftextending forwardly through said upright forward wall for connection tothe gear box.

1. Boat hull construction comprising walls forming side and transomfairing surfaces determining the outer contour of said walls, said wallsrecessed inwardly from at least one of said fairing surfaces to formseparate compartments for a fuel tank and an engine and adapted toresist explosive pressures within said compartments, at least one of thewalls of each compartment being sloped toward said fairing surface todrain liquids and direct explosive forces outwardly from saidcompartment, and explosion-resistant ducts cOnnecting said compartments.2. Boat hull construction as in claim 1 in which the compartment for theengine is recessed inwardly from the transom and the compartment for thefuel tank is recessed inwardly from one side of the wall.
 3. Boat hullconstruction as in claim 2 in which covers in continuation of said outerwall fairing surfaces are outwardly detachably mounted on saidcompartments.
 4. Boat hull construction comprising walls forming sideand transom fairing surfaces determining the outer contour of said wall,said walls recessed inwardly from said transom fairing surface to forman engine compartment adapted to resist explosive pressures within saidcompartment, at least one of said compartment walls being slopedoutwardly toward said fairing surface to drain liquids and directexplosive forces outwardly from said compartment, said compartmenthaving an upright forward wall, an engine mounted in said compartmentfor propelling the boat through a forward gear box, and a drive shaftextending forwardly through said upright forward wall for connection tothe gear box.